Disposable garment formed from an elastic film laminate

ABSTRACT

PCT No. PCT/US93/05649 Sec. 371 Date Mar. 6, 1995 Sec. 102(e) Date Mar. 6, 1995 PCT Filed Jun. 14, 1993 PCT Pub. No. WO94/00292 PCT Pub. Date Jan. 6, 1994An elastic film is provided with non-elastic regions and elastic regions formed from a multi-layer film of an elastomeric layer and relatively inelastic layers(s).

This application is a 371 application of international applicationPCT/US93/05649, filed Jun. 14, 1993.

This application is a 371 application of international applicationPCT/US93/05649, filed Jun. 14, 1993.

FIELD OF THE INVENTION

The invention concerns elastomeric films and more specifically concernsan improved elastomeric laminate.

BACKGROUND

Elastomeric films have for some time been used and discussed in theliterature with regard to their applications in disposable products,such as baby diapers and adult incontinent devices. These elastomericwebs or films are used primarily in the body hugging portions ofgarments. Many of these elastics are temperature-treated to provide forcontrolled elastic recovery. In diapers, for example, elastomeric bandsare typically used in the waistband portions such as discussed in U.S.Pat. No. 4,681,580, issued to Reising et al., and Lash, U.S. Pat. No.4,710,189. Both of these patents describe the use of elastomericmaterials which have a heat stable and a heat unstable form. The heatunstable form is created by stretching the material when heated aroundits crystalline or second phase transition temperature followed by arapid quenching to freeze in the heat unstable extended form. The heatunstable elastomeric film can then be applied to the, e.g., diaper andthen heated to its heat stable elastomeric form.

Berger, U.S. Pat. No. 3,694,815, proposed a method for attaching astretched relaxed elastic ribbon to a garment by stretching conventionalelastic ribbons and immediately freezing the elastomeric material atrelatively extreme low temperatures (e.g., well below ambient).

UK Pat. Application 2190406 A proposed maintaining a conventionalelastomer in a stretched condition, while attaching it to the member tobe shirred (e.g., a diaper), by a rigidifying member, which would thenbe removed or destroyed following the attachment procedure. Asdescribed, the elastomers are first stretched then applied to therigidifying member in its stretched form.

Matray et al., UK Pat. 2,160,473, proposes an elastomer which willshrink at an elevated temperature (e.g., at or above 175° F. or 79.4°C.). The allegedly novel feature of this material, compared to the heatshrink materials discussed above, is that it does not require preheatingor cold treatment during the stretching operation but rather could bestretched at ambient temperatures by a differential speed roll processor by "cold rolling". The polymer proposed was a copolymer havingalternating segments of polyamidepolyether block polymers, commerciallyavailable under the trade name Pebax, particularly Pebax Extrusiongrades 2533 and 3533.

Problems with these elastomeric films include the difficulties inherentin applying a stretched elastic film to a flexible substrate such as adisposable diaper. For example, these film elastics, after beingattached to a flexible substrate, such as by adhesives, will place shearstresses on the attachment areas. This can result in the elasticdetaching from the flexible substrate, particularly after repeatedelongations.

In copending PCT Application No. US90/05783, filed Oct. 10, 1990 (WO91/07277, published 30 May 1991), having a common assignee, there isdisclosed an elastomeric laminate having at least one elastomeric layerand at least one skin layer which addresses some of the above-notedproblems in the art.

Despite the numerous advantages in the materials of the copendingapplication, there is room for improvement for some applications. Inorder to activate the nonelastomeric laminate into a state that willallow it to recover and become elastomeric, the laminate must bestretched a substantial amount, for many materials contemplated asuseful for the skin and core layers. Further, when the elastic isapplied to a garment, equally high stretch ratios are generally requiredto provide sufficient elastic force to functionally elasticize thegarment. This is problematic for applications where low elastic stretchratios would be desirable, for example, when high levels of gathering ofa garment is undesirable or where required by manufacturing needs. Thereis also a need for elastics that will provide elasticity only inspecified areas without requiring the application of separate discreteelastic elements at each area.

The desirability of obtaining elasticity in specified areas of a ribbonor tape-like substrate is illustrated by U.S. Pat. Nos. 3,800,796,4,834,820, 4,778,701 and 4,227,952, which disclose the use of compositematerials designed to have specified areas of elasticity for use indiaper systems. However, these composites require complicatedconstruction mechanisms to bring the diverse elements of the compositetogether and/or special procedures for their manufacture and use, thatlimit their general applicability.

SUMMARY OF THE INVENTION

The present invention relates to improved non-tacky, microtextured,multi-layer elastomeric laminates. The laminates of the presentinvention are comprised of an elastomeric polymeric core layer(s), whichprovides elastomeric properties to the laminate and one or morepolymeric skin layers. Laminates can be prepared by coextrusion of theselected polymers for the skin and core layers or by application of oneor more elastomer layer(s) onto one or more already formed skinlayer(s). The novel, non-tacky microtextured laminate is obtained bystretching the laminate past the elastic limit of the skin layers and,while the laminate is stretched, selectively deactivating the elasticityof the laminate at predetermined regions. The laminate then recovers, inthe non-deactivated regions, which can be instantaneous, over anextended time period, which is skin layer controllable, or by theapplication of heat, which is also skin layer controllable.

The selectively deactivated areas provide high-strength inelasticregions. The recovered regions can be microtextured or have detachedskin layers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a process and apparatus used tocoextrude the laminates of the invention.

FIG. 2 is the cross-sectional segment of a laminate withmicrostructuring caused by uniaxially stretching a film of theinvention.

FIG. 3 is a perspective view of a microtextured skin embodiment of theinvention.

FIG. 4 is a perspective view of a delaminated skin embodiment of theinvention.

FIG. 5 is a diaper tape tab formed of the invention laminate.

FIG. 6 is an end view of the FIG. 4 embodiment as it would appear in adiaper.

FIG. 7 is a perspective view of a delaminated skin embodiment as in FIG.4 laminated to a nonwoven having a large central nonelastic region suchas would be suited as a disposable training pant with elastic sidepanels.

FIG. 8 is a plan view of a laminate such as in FIG. 7 having a largecentral nonelastic region.

FIG. 9 is an alternative embodiment of FIG. 8 having nonelastic outeredge regions.

FIG. 10 is a perspective view of a training pant using the laminate ofthe invention as an outer cover sheet.

FIG. 11 is a top view of a training pant using the laminate of theinvention as an outer cover sheet.

FIG. 12 is a top view of an alternative embodiment of a training pantusing the laminate of the invention as an outer cover sheet.

FIG. 13 is a perspective view of a resealable training pant using thelaminate of the invention as an outer cover sheet.

FIG. 14 is a top view of the training pant of FIG. 13 in an opencondition.

FIG. 15 is a perspective view of an alternative embodiment of aresealable training pant using the laminate of the invention as an outercover sheet.

FIG. 16 is a top view of an alternative embodiment of FIG. 15 using thelaminate of the invention as an outer cover sheet.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention relates broadly to novel non-tacky, multi-layerelastomeric laminates comprising at least one elastomeric core layer andat least one relatively nonelastomeric skin layer. The skin layer(s) arestretched beyond their elastic limit and recovered in selected,non-deactivated, areas with the core layer so as to form elasticregions. Microtexture or microstructure means that the layer containspeak and valley irregularities or folds which are large enough to beperceived by the unaided human eye as causing increased opacity over theopacity of the laminate before microtexturing, and which irregularitiesare small enough to be perceived as smooth or soft to human skin.Magnification of the irregularities is required to see the details ofthe microtexture.

The elastomer can broadly include any material which is capable of beingformed into a thin film layer and exhibits elastomeric properties atambient conditions. Elastomeric means that the material willsubstantially resume its original shape after being stretched. Further,preferably, the elastomer will sustain only small permanent setfollowing deformation and relaxation, which set is preferably less than20 percent and more preferably less than 10 percent of the originallength at moderate elongation, e.g., about 400-500%. Generally, anyelastomer is acceptable which is capable of being stretched to a degreethat causes relatively consistent permanent deformation in a relativelyinelastic skin layer. This can be as low as 50% elongation. Preferably,however, the elastomer is capable of undergoing up to 300 to 1200%elongation at room temperature, and most preferably up to 600 to 800%elongation at room temperature. The elastomer can be both pureelastomers and blends with an elastomeric phase or content that willstill exhibit substantial elastomeric properties at room temperature.

Heat-shrink elastomers are contemplated for use in the presentinvention, however, non-heat-shrinkable elastomers can be used whileretaining the advantages of heat shrinkability in selected embodiments.Non-heat-shrinkable means that the elastomer, when stretched, willsubstantially recover, sustaining only a small permanent set asdiscussed above. Non-heat-shrinkable polymers include block copolymerssuch as those known to those skilled in the art as A-B or A-B-A blockcopolymers. These block copolymers are described, for example, in U.S.Pat. Nos. 3,265,765; 3,562,356; 3,700,633; 4,116,917 and 4,156,673, thesubstance of which are incorporated herein by reference.Styrene/isoprene, butadiene or ethylene-butylene/styrene (SIS, SBS orSEBS) block copolymers are particularly useful. Other useful elastomericcompositions can include elastomeric polyurethanes, ethylene copolymerssuch as ethylene vinyl acetates, ethylene/propylene copolymer elastomersor ethylene/propylene/diene terpolymer elastomers. Blends of theseelastomers with each other or with modifying non-elastomers are alsocontemplated.

Viscosity reducing polymers and plasticizers can also be blended withthe elastomers such as low molecular weight polyethylene andpolypropylene polymers and copolymers, or tackifying resins such asWingtack™, aliphatic hydrocarbon tackifiers available from GoodyearChemical Company. Tackifiers can also be used to increase theadhesiveness of an elastomeric layer to a skin layer. Examples oftackifiers include aliphatic or aromatic hydrocarbon liquid tackifiers,polyterpene resin tackifiers, and hydrogenated tackifying resins.Aliphatic hydrocarbon resins are preferred.

Additives such as dyes, pigments, antioxidants, antistatic agents,bonding aids, antiblocking agents, slip agents, heat stabilizers,photostabilizers, foaming agents, glass bubbles, reinforcing fiber,starch and metal salts for degradability or microfibers can also be usedin the elastomeric core layer(s).

The skin layer can be formed of any semicrystalline or amorphous polymerthat is less elastic than the core layer(s) and will undergo permanentdeformation at the stretch percentage that the elastomeric laminate willundergo. Therefore, slightly elastomeric compounds, such as someolefinic elastomers, e.g. ethylene-propylene elastomers orethylene-propylene-diene terpolymer elastomers or ethylenic copolymers,e.g., ethylene vinyl acetate, can be used as skin layers, either aloneor in blends. However, the skin layer is generally a polyolefin such aspolyethylene, polypropylene, polybutylene or apolyethylene-polypropylene copolymer, but may also be wholly or partlypolyamide such as nylon, polyester such as polyethylene terephthalate,polyvinylidene fluoride, polyacrylate such as poly(methylmethacrylate)(only in blends) and the like, and blends thereof. The skinlayer material can be influenced by the type of elastomer selected.Skin-to-core layer contact in the FIG. 3 embodiment has been found tofollow three modes; first, full contact between the elastomeric corelayer and microtextured skin layer; second, full contact with cohesivefailure of the core under the microtextured skin folds; and third,adhesive failure of the skin to the core under the microtexture foldswith intermittent skin/core contact at the fold valleys.

The skin layer, preferably inelastic, used in conjunction with anelastomeric core layer will form at least one outer layer of thelaminate. Used as either an outer or inner layer, the skin layer willmodify the elastic properties of the elastomeric laminate when incontact with the elastomeric layer by any of the three above-describedmodes.

Additives useful in the skin layer include, but are not limited to,mineral oil extenders, antistatic agents, pigments, dyes, antiblockingagents, provided in amounts less than about 15%, starch and metal saltsfor degradability and stabilizers such as those described for theelastomeric core layer.

Other layers may be added between the core layer and the outer layers,such as interlayers to either increase or decrease the bonding of theskin and core layers. Tie layers can be formed of, or compounded with,typical compounds for this use including maleic anhydride modifiedelastomers, ethyl vinyl acetates and olefins, polyacrylic imides, butylacrylates, peroxides such as peroxypolymers, e.g., peroxyolefins,silanes, e.g., epoxysilanes, reactive polystyrenes, chlorinatedpolyethylene, acrylic acid modified polyolefins and ethyl vinyl acetateswith acetate and anhydride functional groups and the like, which canalso be used in blends or as compatibilizers or delamination-promotingadditives in one or more of the skin or core layers.

The shrink recovery mechanism of the laminate, after stretching andselective deactivation, depends on the conditions of film formation, thenature of the elastomeric layer(s), the nature of the skin layer(s), themanner in which the laminate film is stretched and the relativethicknesses of the elastomeric and skin layer(s). By controlling thesevariables, the laminate film can be designed to instantaneously recover,recover over time or recover upon heat activation. Generally, thecore-to-single skin layer ratio will be at least 3, preferably, at least5 and less than about 100 and most preferably at least 5 to about 75.The overall laminate thickness will be at least 1 mil, preferably atleast 2 mils, although preferably less than 10 mils for cost andperformance considerations. At core-to-skin layer ratios less than 3,the laminate has a tendency to not recover when stretched. A stretchedand selectively deactivated laminate capable of instantaneous shrink isone in which the stretched, non-deactivated areas of the elastomericlaminate will recover more than 15% in 1 sec. A laminate capable of timeshrink is one where the 15% recovery point takes place more than 1 sec.,preferably more than 5 sec., most preferably more than 20 sec. afterstretch, and a laminate capable of heat shrink is where less than 15%shrink recovery occurs to the laminate in the first 20 seconds afterstretch and will remain capable of heat shrink for weeks after it isstretched. Percent recovery is the percent that the amount of shrinkageis of the stretched length minus the original length of the activatedarea. For heat-shrink laminates there will be an activation temperaturewhich will initiate significant heat-activated recovery. The activationtemperature used for a heat-shrink laminate will generally be thetemperature that will yield 50% of the total possible recovery(T_(a-50)) and preferably this temperature is defined as the temperaturewhich will yield 90% (T_(a-90)) of the total possible recovery. Totalpossible recovery includes the amount of preactivation shrinkage.

Generally, where the skin layer is relatively thin, the laminate willtend to contract or recover immediately in the non-deactivated areas.When the skin thickness is increased sufficiently the laminate canbecome heat shrinkable in the non-deactivated regions or areas. Thisphenomenon can occur even when the elastomeric layer is formed from anon-heat shrinkable material. By careful selection of the thicknesses ofthe elastomeric layer and the skin layer(s), the temperature at whichthe laminate recovers by a set amount can be controlled. This is termedskin controlled recovery, where generally by altering the thickness orcomposition of the skin, one can raise the elastic recovery activationtemperature of an elastomeric core by a significant degree, generallymore than at least 10° F. (5.6° C.) and preferably by 15° F. (8.3° C.)and more. Although any skin thickness which is effective can beemployed, too thick a skin will cause the laminate to remain permanentlyset when stretched. Generally, where a single skin is less than 30% ofthe laminate this will not occur. For most heat or time shrinkmaterials, the stretched non-deactivated regions of the elastomericlaminate must be cooled so that the energy released during stretchingdoes not cause immediate heat activated elastic recovery. Fine tuning ofthe shrink recovery mechanism can be accomplished by the degree that theactivated regions are stretched.

Improvements in the laminate structure of this invention over that ofcopending application U.S. Ser. No. 07/438,593 lie in a laminate filmhaving elastic properties at selected regions or zones separated bythin, non-elastic regions or zones. The elastic regions or zones arecharacterized by a microtextured surface on the skin layers or, in apreferred embodiment, a thin, skin layer selectively secured to theelastomeric layer in the thin non-elastic regions or zones (FIG. 4). Inthis preferred embodiment, detached skin layer material 13 in theelastic zones or regions 12 allows the elastomeric core layer 14 torecover uninhibited without the skin layer 13 effecting the elasticproperties. However, the skin layer 13 provides a continuous unstressedattachment surface for securing the elastic 20 to substrates to beelasticized, without having to directly adhere the elastic to thesubstrates (FIG. 6). Conventional methods of securing stressed elasticdirectly to a substrate are problematic. An elastic under stress whenattached to a substrate creates shear forces that can cause detachmentof the elastic, stress relaxation of the elastic or reduction in elasticproperties. The FIG. 4 elastic 20 is not directly attached to thesubstrate when it is under stress. The elastic 20 can be easily andsecurely attached to a substrate while avoiding the above-noted problemswith conventional elastic. The preferred elastic 20 of FIG. 4 furtherprovides a breathable securement due to channels 15, particularly usefulin garment applications.

The non-elastic regions 11 are characterized by a smooth layer oforiented skin layer material secured to a reduced thickness elastomericcore layer 14. The elastomeric core layer 14 is unstressed in thisnon-elastic region 11 and generally thinner than the elastomeric layer14 in adjacent recovered elastic regions or zones 12. These non-elasticregions 11 provide secure unstressed attachment points for the elasticlaminate 10 or 20. The non-elastic regions 11 also provide reinforcementzones between the elasticized regions reducing the possibility ofdeformation of the elastic laminate, or attached substrates, when understress.

In the FIG. 4 embodiment, the elastic laminate 20 can be continuouslysecured to a substrate by the skin layer 13. However, the elasticregions will be unattached and free to contract with its full elasticforce when stretched. The secured skin layer, in both the elasticregions 12 and non-elastic regions 11, will keep the elastic in placeand also serve as a reinforcement element for the substrate to which theelastic 20 is attached.

With the FIG. 3 embodiment, the elastic regions 12 will be microtexturedtending to create a mechanical release layer. The elastic of thisembodiment can therefore be applied to substrates with a uniformadhesive coating. The elastic regions will then preferentially detach,allowing the elastic to stretch and elastically recover, while remainingsecurely attached to the substrate in the non-elastic zones or regions11.

A preferred mechanism for forming the film laminate by extrusion isshown in FIG. 1 where D, D' and D" are feedblocks or manifolds. D, D'and D" can be separate or combined, or a part of die E. E is aconventional multiple layer die or a combining adapter and die such asdisclosed in U.S. Pat. Nos. 4,152,387 or 4,197,069 (Cloeren). As shown,feedblocks or manifolds can be used to feed into each layer passagewayof the multiple layer die E or to only a single passageway of such a die(e.g., with a combining adaptor in the feedblock region). AA, BB, and CCare extruders. AA', BB' and CC' are streams of thermoplastic materialbeing extruded into the feedblocks or manifold die. E is the 3 or morelayer (e.g., 5-layer) die, F is a heated casting roll, and G and H arerolls to facilitate take-off and roll-up of the laminate. Nip rollerscan also be provided.

The die and feedblock used are typically heated to facilitate polymerflow and layer adhesion. The temperature of the die depends upon thepolymers employed and the subsequent heat treatment steps. Generally thetemperature of the die is not critical but temperatures are generally inthe range of 350° to 550° F. (176.7° to 287.8° C.) with the polymersexemplified.

Whether the laminate is prepared by coating, lamination, sequentialextrusion, coextrusion or a combination thereof, the laminate formed andits layers will preferably have substantially uniform thicknesses acrossthe laminate. Laminates prepared in this manner have generally uniformproperties with a minimum of edge effects such as curl, modulus change,fraying and the like.

After formation, the laminate is stretched past the elastic limit of theskin layer(s), which deform. The stretched laminate is then subjected tolocalized heat treatment to selectively relax or deactivate the elasticin certain regions or zones. This allows the oriented elastic in thetreated regions to locally randomize to form a dimensionally stableelastic material in these regions or zones. The localized heat treatmentmust be long enough to release stresses in the deformed unstableelastic.

The now localized heat treated laminate is recovered, as discussed abovein the non-heat treated, or non-deactivated, regions or zones. Forheat-activated recovery, the inherent temperature of heat activation isdetermined by the materials used to form the elastic layer of thelaminate in the first instance. However, for any particular laminate theactivation temperature, for example, either T_(a-50) or T_(a-90), can beadjusted by varying the skin/core ratio of the laminate, adjusting thepercent stretch or the overall laminate thickness. The activationtemperature used for a heat-shrink laminate is generally at least 80° F.(26.7° C.), preferably at least 90° F. (32.2° C.) and most preferablyover 100° F. (37.8° C.). When forming a heat activatable laminate, thestretched and locally heat treated laminates are quenched on a coolingroller, which prevents the heat generated during elongation fromprematurely activating laminate recovery in the remaining activatedregions. The chill roll temperature is maintained below the activationtemperature.

FIG. 2 is a schematic diagram of the common dimensions which arevariable for uniaxially stretched and recovered laminates in theactivated or recovered microtextured regions. The general texture is aseries of regular repeating folds. These variables are the total heightA-A', the peak to peak distance B-B' and the peak to valley distanceC-C'. These variables were measured for a series ofpolyolefin/styrene-isoprenestyrene/polyolefin laminates. General rangesfor A-A', B-B' and C-C' were noted. For total height (A-A'), the rangemeasured was from 0.79 to 32 mils(0.02 to 0.81 mm). For peak-to-peakdistance (B-B'), or the fold period, the measured range was from 0.79 to11.8 mils(0.02 to 0.30 mm). For peak-to-valley distance (C-C'), themeasured range was from 0.04 to 19.7 mils(0.001 to 0.5 mm).

The elastomeric laminates prepared in accordance with the invention, canalso be described in terms of increase in skin surface area. Where themicrotextured laminate shows heavy textures, the surface area willincrease significantly. As the stretch ratio increases, so does thepercent increase in surface area, from the unstretched to the stretchedand recovered laminate. Generally, the skin surface area will increaseby at least 50%, preferably by at least 100% and most preferably by atleast 250% in the stretched and recovered areas or regions. The increasein surface area directly contributes to the overall loft, texture andfeel of the laminate surface when microstructured or when the skindetaches from the elastic core.

For those constructions prone to delamination, a brief relaxing orannealing following activation may be used to counteract this tendency,if desired. This brief annealing step will release residual unstableorientation at the elastomeric layer and skin layer interface,particularly for elastic between folds of the microstructured skinlayer. The annealing would generally be above the glass transition pointtemperature (T_(g)) of the elastomer, above the B block T_(g) for ABAblock copolymers, but below the skin polymer melting point. A lowerannealing temperature is generally sufficient. The annealing willgenerally be for longer than 0.1 seconds, depending on the annealingtemperature, followed by cooling to room temperature in the relaxedannealed state. With commercial ABA block copolymers (e.g., Kraton™1107), an annealing or relaxing temperature of about 75° C. is found tobe sufficient. If it is preferred to create delamination of the skin inthe elastic regions, this annealing step should be avoided prior todelamination.

FIG. 3 is an example of a film that has been stretched and locally heattreated to create non-elastic deactivated regions 11 and allowed torecover in elastic regions 12. The elastic has been locally heat treatedas bands extending transverse to the stretch direction. However, thelocalized heat treatment and deactivation can extend in bands in theelongation direction, multiple directions or in patterns to createelastics where the localized heat treated deactivated regions or zonescan selectively buckle. In FIG. 3, the elastic regions 12 of the elasticlaminate 10 have microtextured skin layers.

In some embodiments, the skin layer can be selectively detached in theactivated elastic areas 12 to form the elastic regions 12 of FIG. 4 by,e.g., working the film in conjunction with a delaminating heattreatment. This detachment process is dependent on the relativeadhesiveness of the skin and core layers and the thickness of the skinand core layers. Additives can be added to the skin and/or core layersto promote delamination, such as polymers or release agents incompatiblewith the polymer in the adjacent layer that tends to separate theinterlayer interface. For example, it has been found that polystyreneand oil added to an A-B block copolymer core promote delamination ofpolyolefin skin layers, while ethylene vinyl acetate orpolyalphamethylstyrene added to the polyolefin skin layers also promotesdelamination.

FIG. 4 displays the embodiment where the skin layer 13 is selectivelydetached from the elastomeric core layer 14. In the locally heat-treatednon-elastic regions 11, the oriented skin layer 13 remains securelybonded to the elastomeric core layer 14, as well as strengthened due tothe orientation and subsequent localized heat treatment. The elastomericcore layer 14 in regions 11 (as in FIG. 3) is thin relative to theelastomeric core layer in elastic regions 12. The detached skin layer 13in elastic regions 12 provides an attachment surface in the elasticregions 12 while avoiding the above discussed problematic directattachment of a substrate to the elastomeric layer 14.

The FIG. 4 elastic 20 also provides air channels 15. These channels 15can provide breathability to elasticized regions of a garment, or thelike, such as a cuff or diaper waistband or leg band.

The laminate of FIGS. 3 and 4 can be extensively used in disposablediapers, for example as a waistband, located in either the front or sideportions of the diaper at waist level, as leg elastic, as an outer coversheet or in elasticated slip-on diapers or training pants, where theelastomeric laminate could be used as, or in, side panels around the hipthat have zones of elasticity to create a tight fitting garment. Thelaminates can be applied as continuous or intermittent lengths byconventional methods. When applied, a particular advantage of theelastic laminate 20 with delaminated skin (e.g., the FIG. 4 embodiment),is that extremely uniform shirring can be easily obtained by applyingelastic laminates with substantially flat non-elastic regions 11 whilethe elastic regions 12 are stretched. When the elastic regions 12recover, the FIG. 6 garment layers 18 and 19 will shirr only in thoseregions with skin delamination, i.e. the elastic regions 12, and shirruniformly in elastic regions 12 (i.e., as a single gather). This allowsone to predictably and easily control garment shirring, a property notpossible with conventional film elastics.

Similar uniform shirring can be obtained with the FIG. 3 embodiment byzone release coating the elastic laminate 10 in elastic regions 12. Therelease coating can be a conventional low adhesion coating or in apreferred arrangement an oil, such as mineral oil. The oil is preferreddue to cost and ease of application. The oil has not been found tomigrate when the elastic 10 is wound in a roll form as would be expectedfor a conventional film. It is believed that oil migration is arrestedby the microtextured skin layer surface in the oil-coated area.

When an elastic laminate with flat non-elastic regions 11 as shown inFIGS. 3 and 4, is attached to a garment; as shown in FIG. 6, the elasticalso provides improved elastic stress at low elongations of the elasticlaminate 10, versus a continuous elastic film. The elongational stressesin this arrangement are preferentially confined to the elastic regionswhich proportionally provide increased elastic stress or force.

The elastomeric laminate can be adhered to a garment by ultrasonicwelding, heat sealing and adhesives such as pressure-sensitiveadhesives, by conventional methods. The adherence would be preferably inat least the locally heat treated non-elastic regions 11.

Another use for the invention laminates would be as an elasticizeddiaper fastening tab as per, e.g., U.S. Pat. No. 3,800,796, as shown inFIG. 5. The elastic zone 6 can be placed at the desired location whileproviding selectively deactivated non-elastic end regions 7 and anelastic central region 6. Adhesive 8 could then be applied to one ormore faces of the inelastic end regions 7.

The laminate of FIG. 7 is an example of a suitable construction for useas an outer cover sheet or an elastic panel in an elasticated disposablegarment such as a slip-on diaper or training pant using the laminate ofFIG. 4. The laminate of FIG. 3 could also be employed in theconstruction depicted in FIG. 7 (as well as FIGS. 8-16). Elasticportions 21 and 23 of the elastic laminate construction 30 would bejoined to form elasticated side panels around the hip of the wearer. Thenon-elastic portion 22 would be formed in a manner similar tonon-elastic regions 11 and would be joined to the absorbent pad at anend thereof, preferably to a liquid-impermeable outer cover layer forthe absorbent pad. Alternatively, the non-elastic portion 22 couldprovide the liquid-impermeable outer cover layer on the absorbent padstructure of the elasticated diaper or training pant. In a preferredarrangement, the elastic laminate 30 further comprises a nonwoven layer24 attached to at least one face of a laminate providing reinforcementand softness to the elastic material.

FIG. 8 illustrates a possible construction employing an elasticlaminate, such as described in FIG. 7, or versions using the FIG. 3elastic laminate, with or without nonwoven layers laminated thereto. Thelaminate 40 would be in the form of a continuous web which would be cutinto discrete units such as shown in FIG. 8 optionally provided withelastic 44 and 43 to provide waist elastication for the disposablegarment. The garment would further be converted by cutting out portions41 and 42 to provide for the legs of a wearer.

An alternative embodiment is depicted in FIG. 9 where an additionalnon-elastic region 51 and 52 is provided on the outer edges of theelastic portions 21 and 23 as sealable strips. The FIGS. 8 and 9laminates can be formed into a garment such as shown in FIG. 10, whichcan be of a construction such as shown in FIG. 11 where the outer sideedges 61 or 62 of the laminates 40 or 50 would be sealed at a side seam63 to form a pant-type garment with elastic side panels formed byjoining of the elastic portions 21 or 23. An absorbent pad would beplaced adjacent the non-elastic region 22 of the laminate, which wouldfurther be covered by a conventional liquid-permeable inner layer ortopsheet 65, which could also cover the inner face of the elasticlaminate 40 or 50. The absorbent 64 can be applied to the laminate byany conventional means including the use of a hot-melt adhesive whichcan also be used to attach the topsheet 65.

An alternative embodiment for employing a laminate, such as shown inFIG. 7, in a disposable diaper or training pant, is depicted in FIG. 12.In this embodiment, the absorbent pad is sandwiched between theliquid-permeable topsheet 65 and a liquid-impermeable cover sheet 66 toform a composite structure 60. The central non-elastic region 22 of astrip of an elastic laminate, such as shown in FIG. 7, is then attachedto a first front end 74 portion of the pad composite structure 60,preferably to the liquid-impermeable outer sheet 66. The outerlongitudinal side edges 71 and 72 of the elastic regions 21 and 23 arethen attached to the opposite back end portion 75 of the pad compositestructure 60 at attachment region 73 by conventional means. The sideedges 71 and 72 can be elastic or non-elastic, however, preferably arenon-elastic to enhance adhesion. The side edges 71 and 72 can be adheredto either the outer face of the nonwoven topsheet 65, or theliquid-impervious outer sheet 66, or sandwiched therebetween.Preferably, edges 71 and 72 are attached to the outer face of theliquid-impervious outer sheet 66, as shown in FIG. 12. The width of theelastic panel 70 would preferably be similar to the width of laminates40 and 50 along the longitudinal seams 63, as shown in FIGS. 10 and 11.Alternatively, non-elastic region 22 can be attached to the oppositeback end portion 75 of the absorbent pad composite 60 with the edges 71and 72 attached to a first front end 74 of the pad composite 60.

FIGS. 13 and 14 (elastic band 80 is enlarged to show detail) display analternative embodiment where the elastic composite is releasably orresealably attached to a front portion 81 of an absorbent pad composite60. The absorbent pad composite 60 is provided with leg elastics 86 and87 and waist elastic 88 and 89. The non-elastic region 22 of an elasticband 80 is attached to the liquid-impervious outer cover sheet 64 at aback end 75 of the absorbent pad composite 60. At the outer side edgesof the elastic regions 21 and 23 are provided attachment regions 82 and83, which preferably are non-elastic. On the attachment regions 82 and83 are provided a pair of first attachment means 85 and 84,respectively, which releasably attach to one or more secondcomplementary attachment means 81 at a front end 74 of the absorbent padcomposite 60. The first attachment means 84 and 85 can be a conventionalattachment means such as a pressure-sensitive adhesive patch, amechanical fastener patch or a cohesive adhesive patch. A fastening tabcould also be used (not shown) where the tab is permanently attached tothe attachment regions (82 or 83) at one end and provided with theattachment means (84 or 85) at a distal end. A complementary attachmentmeans 81 would comprise a region suitable matched to thepressure-sensitive adhesive on attachment regions 82 and 83 (such as aplastic landing strip or otherwise reinforced portion of theliquid-impervious backsheet 64, if necessary). Zone 81 would alsoinclude a mechanical fastening element complementary to the mechanicalfastening elements on 85, or a suitable matched cohesive adhesive.Although less preferred, an elastic laminate band 80 can also bereleasably attached to the rear end 75 of the absorbent pad 60 with thenon-elastic region 22 permanently adhered to the front end 74 of theabsorbent pad 60.

FIGS. 15 and 16 (elastic band 90 is enlarged to show detail) display analternative version of a detachable and resealable pant design employingan elastic laminate band 90 provided with a fastening tab 91 as theattachment means. The fastening tab 91 is permanently adhered at a firstend 93 to an attachment region 92 of the elastic laminate band 90, whichregion is preferably non-elastic. This permanent attachment can beachieved by conventional means such as adhesive bonding, heat sealing orultrasonic welding. The distal end 94 of the fastening tab 91 would beprovided with a suitable attachment means to releasably engage with theouter face of the opposing elastic portion (21 or 23) of the elasticband 90. Either of the opposing elastic portions can also be providedwith a fastening means (e.g., a pressure-sensitive adhesive patch or tabto engage the absorbent pad composite). Preferably, this attachmentmeans on the distal end 94 would comprise male mechanical fastenerelements, which would releasably engage with a nonwoven or foraminousmaterial laminated to the outer face of the elastic band 90, such asshown in FIG. 7. Pressure-sensitive adhesive could also be used on thedistal end 94 of fastening tab 91 as the attachment means.

A further embodiment of the invention is an anisotropic film that willbe non-elastic on a first axis and elastic or extensible on an axisorthogonal to the first axis. The film non-elastic axis is provided bystretching an elastic laminate, then subjecting the entire stretchedlaminate to a deactivating heat treatment rather than merely a localizeddeactivating heat treatment. The skin layer will then be oriented andstrengthened in the direction or axis of stretch and substantiallynon-extensible on this axis. However, the film in the orthogonal orcross direction will be readily extensible or elastic, if subsequentlystretched and allowed to recover. This anisotropic quality renders thisfilm particularly well suited to applications where a film is desiredthat is strong in one direction yet conformable in the cross direction.For example, a sealing pressure-sensitive adhesive tape to be applied toan uneven surface such as a pipe fitting or screw threads isadvantageously conformable in the cross direction to sealingly engageall surfaces, despite their variation in diameter, yet strong in thelongitudinal direction.

The following Examples are provided to illustrate presently contemplatedpreferred embodiments and the best mode for practicing the invention,but are not intended to be limiting thereof.

EXAMPLES

A continuous coextrusion process was carried out to prepare three layerfilm laminates having two outer inelastic skin layers and an elastomericcore layer. One extruder was used to feed the elastomeric core layermaterial and a second extruder was used to feed the inelastic skin layermaterial into a three-layer Cloeren™ feedblock, and the resultinglayered melt was extruded through a single manifold film die and castonto a cast roll. Feedblock and die temperatures ranged fromapproximately 400-540 deg F. (204-282 deg C.) and the cast rolltemperatures ranged from approximately 70-180 deg F. (21-82 deg C.).Line speeds averaged approximately 30 feet(9.14 m) per minute. Filmlaminate total thicknesses ranged from 3-10 mils (0.076-0.254 mm) andcore to skin (C/S) ratios varied from 4:1 to 10:1. Film compositions,feedblock and die temperatures, cast roll temperatures, C/S ratios andtotal film thicknesses (in mils) are given in Table I.

A localized heat treatment was used to create non-elastic regions orzones on the elastic laminates. A three inch (7.62 cm) wide sample offilm was first stretched in the transverse direction (TD) at a ratio offrom about 3:1 to 6:1 and then was passed over a patterned heated rollwhich resulted in parallel longitudinal bands of inelastic regionsrunning in the machine direction (MD) of the film. Heating temperaturesranged from about 150-180 deg F. (66-82 deg C.).

A cyclical stretching and heating process was used to affectdelamination of the outer inelastic skin layers from the elastomericcore layer in the elasticized regions of the film laminates. A 1.0 inch×3.0 inch (2.54 cm×7.62 cm) sample (MD by TD) of film was stretched inthe transverse direction to just before break (95-150%), which activatedthe locally non-heat treated regions. The film was then placed in astream of hot air supplied by a heat gun (approximately 140 deg F. or 60deg C.). The film was heated until the elasticized regions were fullycontracted and warmed (<1 minute). The film was then removed from theheat and was stretched by hand in the transverse direction until justbefore break, and then immediately allowed to recover. The film washeated once again (<1 minute), then was cyclically stretched andimmediately released, in the transverse direction. This heating andstretching process was repeated until an observation of delamination orno delamination could be made. Delamination occurring after 3-10 cycleswas considered excellent. The extent of delamination was evaluatedvisually and was classified as no delamination (0), delaminationdifficult (1), good delamination (2), delaminates easily, or excellent(3), and delaminates very easily (4). Delamination observations aregiven in Table II.

                                      TABLE I                                     __________________________________________________________________________                              Film Feedblock                                                                           Cast                                        Skin  Core          C/S                                                                              Thickness                                                                          & Die Temp.                                                                         Roll Temp.                               Ex.                                                                              Composition                                                                         Composition                                                                         Additives in Core                                                                     Ratio                                                                            (microns)                                                                          °F. (°C.)                                                             °F. (°C.)                  __________________________________________________________________________     1 PP 3085                                                                             K-1657                                                                              NONE    10 3 (76)                                                                             450 (232)                                                                           80 (27)                                   2 PP 1024                                                                             K-1657                                                                              NONE    10 3 (76)                                                                             450 (232)                                                                           72 (22)                                   3 PP 1024                                                                             K-1657                                                                              10% PS-G3                                                                             7  3 (76)                                                                             450 (232)                                                                           80 (27)                                   4 PP 1024                                                                             K-1657                                                                              10% PS-666                                                                            7  3 (76)                                                                             450 (232)                                                                           120 (48)                                  5 PP 1024                                                                             K-1657                                                                              15% PS-666                                                                            7  3 (76)                                                                             450 (232)                                                                           120 (48)                                  6 PP 1024                                                                             K-1657                                                                              20% PS-666                                                                            7  3 (76)                                                                             450 (232)                                                                           120 (48)                                  7 PP 1024                                                                             K-1657                                                                              10% PS-615                                                                            5    3.5 (89)                                                                         450 (232)                                                                           180 (82)                                  8 PP 1024                                                                             K-1657                                                                              10% PS-615                                                                            7    3.5 (89)                                                                         450 (232)                                                                           180 (82)                                  9 PP 1024                                                                             K-1657                                                                              10% PS-615                                                                            7    3.5 (89)                                                                         450 (232)                                                                           120 (48)                                 10 PP 1024                                                                             K-1657                                                                              10% PS-615                                                                            7    3.5 (89)                                                                         450 (232)                                                                           80 (27)                                  11 PP 1024                                                                             K-1107                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             400 (204)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           12 PP 3445                                                                             K-1107                                                                              10% PS-615 +                                                                          5    3.3 (84)                                                                         420 (216)                                                                           70 (21)                                                 1% IRGANOX                                                                    1076                                                           13 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         411 (211)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           14 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         435 (224)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           15 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         460 (238)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           16 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         480 (249)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           17 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         500 (260)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           18 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         520 (271)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           19 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5.5                                                                                3.5 (89)                                                                         540 (282)                                                                           80 (27)                                                 1% IRGANOX                                                                    1076                                                           20 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          7  3 (76)                                                                             420 (216)                                                                           70 (21)                                                 1% IRGANOX                                                                    1076                                                           21 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          7  3 (76)                                                                             480   70 (21)                                                 1% IRGANOX      MELT                                                          1076            (249)                                          22 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             480   70 (21)                                                 1% IRGANOX      MELT                                                          1076            (249)                                          23 PP 1024                                                                             K-1657                                                                              5% MINERAL                                                                            7  3 (76)                                                                             450 (232)                                                                           80 (27)                                                 OIL                                                            24 PP 3085                                                                             K-1107                                                                              5% MINERAL                                                                            7    2.5 (64)                                                                         420 (216)                                                                           70 (21)                                                 OIL + 1%                                                                      IRGANOX 1076                                                   25 LDPE 4012                                                                           K-1107                                                                              10% PS-615 +                                                                          7    2.5 (64)                                                                         420 (216)                                                                           70 (21)                                                 1% IRGANOX                                                                    1076                                                           26 HDPE 52053                                                                          K-1107                                                                              10% PS-615 +                                                                          7    2.5 (64)                                                                         420 (216)                                                                           70 (21)                                                 1% IRGANOX                                                                    1076                                                           27 PP 1024                                                                             K-1657                                                                              10% PS-615                                                                            5    3.5 (89)                                                                         450 (232)                                                                           120 (48)                                 28 90% PP                                                                              K-1657                                                                              10% PS-615                                                                            5  3 (76)                                                                             450 (232)                                                                           120 (48)                                    1024 + 10%                                                                    EVA 260                                                                    29 PP 3085                                                                             K-1107                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             450 (232)                                                                           70 (21)                                                 1% IRGANOX                                                                    1076                                                           30 95% PP                                                                              K-1107                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             450 (232)                                                                           70 (21)                                     3085 + 5%   1% IRGANOX                                                        EVA 260     1076                                                           31 PP 3085                                                                             K-1657                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             450 (232)                                                                           64 (18)                                                 1% IRGANOX                                                                    1076                                                           32 95% PP                                                                              K-1657                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             450 (232)                                                                           64 (18)                                     3085 + 5%   1% IRGANOX                                                        EVA 260     1076                                                           33 90% PP                                                                              K-1107                                                                              10% PS-615 +                                                                          5  3 (76)                                                                             450 (232)                                                                           70 (21)                                     3085 + 10%  1% IRGANOX                                                        PAMS        1076                                                              18-29                                                                      34 PP 3085                                                                             PU 2102-                                                                            NONE    5  3 (76)                                                                             435 (224)                                                                           80 (27)                                           75A                                                                  __________________________________________________________________________

Tensile and elongation data (ASTM D-638 and D-412) were obtained on thesamples using an Instron 1122 Tensile Tester (available from Instron™Corporation). A 0.5 inch×3.0 inch (1.27 cm×7.62 cm) sample was placed ata 2.0 inch (5.08 cm) gauge length and was stretched at a rate of 12inches (30.5 cm) per minute. The tensile and elongation data are givenin Table II.

                                      TABLE II                                    __________________________________________________________________________              Tensile       Tensile                                                         Stress (MD)   Stress (TD)                                                     PSI at Break                                                                        Elongation                                                                            PSI at Break                                                                         Elongation                                     Ex.                                                                              Delamination                                                                         (N/cm.sup.2)                                                                        (MD) % at Break                                                                       (N/cm.sup.2)                                                                         (TD) % at Break                                __________________________________________________________________________     1 1       574  903      690   818                                                       (396)         (476)                                                 2 0       767  859      666   844                                                       (529)         (459)                                                 3 2      2446  800     3018   793                                                      (1687)        (2081)                                                 4 2      2801  901     2592   823                                                      (1931)        (1787)                                                 5 2      2973  886     2961   863                                                      (2050)        (2042)                                                 6 2      2498  766     2243   816                                                      (1722)        (1547)                                                 7 1      2352  697     3263   722                                                      (1622)        (2250)                                                 8 1-2    2586  820     3526   847                                                      (1783)        (2432)                                                 9 2      2514  843     3160   812                                                      (1733)        (2179)                                                10 1      2351  817     2502   793                                                      (1621)        (1725)                                                11 3      2137  739     1884   706                                                      (1473)        (1299)                                                12 3      1818  878     1114   615                                                      (1254)         (768)                                                13 3      1893  809     1828   695                                                      (1305)        (1260)                                                14 3      1796  772     1969   757                                                      (1238)        (1358)                                                15 3      1841  834     1777   737                                                      (1269)        (1225)                                                16 3      1796  868     1256   601                                                      (1238)         (866)                                                17 3      1755  878     1664   781                                                      (1210)        (1147)                                                18 3      1353  868     1144   611                                                       (933)         (789)                                                19 3      1440  770     1112   559                                                       (993)         (767)                                                20 4      1209  670     1389   857                                                       (834)         (958)                                                21 4      1476  812     1338   849                                                      (1018)         (923)                                                22 3      1442  732     1286   766                                                       (994)         (887)                                                23 2      1407  754     1928   812                                                       (970)        (1329)                                                24 4                                                                          25 2                                                                          26 4                                                                          27 1      1883  680     2514   729                                                      (1298)        (1733)                                                28 3      2484  753     2904   727                                                      (1713)        (2002)                                                29 3      1661  800     1511   863                                                      (1145)        (1042)                                                30 4      1602  794     1566   901                                                      (1105)        (1080)                                                31 1      2555  808     2124   756                                                      (1762)        (1464)                                                32 2      2666  828     2541   773                                                      (1838)        (1752)                                                33 4      1878  873     1199   775                                                      (1295)         (827)                                                34 2      3132  589     1343   355                                                      (2160)         (926)                                                __________________________________________________________________________

The following abbreviations are used in Table I to indicate thematerials used in the skin and core layers.

PP 3085 is Escorene™ 3085, a 36 MFI polypropylene available from ExxonCorporation.

PP 3445 is Escorene™ 3445, a 35 MFI polypropylene available from ExxonCorporation.

PP 1024 is Escorene™ 1024, a 12 MFI polypropylene available from ExxonCorporation.

LDPE 4012 is low density polyethylene #4012 available from Dow ChemicalCompany.

HDPE 52053 is high density polyethylene #52053 available from DowChemical Company.

K-1657 is Kraton™ G-1657 a styrene-ethylenebutylene-styrene (SEBS) blockcopolymer available from Shell Chemical Company.

K-1107 is Kraton™ 1107 a styrene-isoprene-styrene (SIS) block copolymeravailable from Shell Chemical Company.

PU 2102-75A is Pellathane™ 2102-75A, a polyurethane available from DowChemical Company.

PS-G3 is polystyrene #G3 available from Amoco Oil Company.

PS-666 is polystyrene #666 available from Dow Chemical Company.

PS-615 is polystyrene #615 available from Dow Chemical Company.

EVA 260 is Elvax™ 660, an ethylene-vinyl acetate copolymer availablefrom I.E. duPont de Nemours Company.

PAMS 18-290 is poly(alphamethylstyrene) #18-290 available from Amoco OilCompany.

Irganox™ 1076 is an anti-oxidant available from Ciba-Giegy Corporation.

Amoco™ White mineral oil #31USP is mineral oil available from Amoco OilCompany.

Examples 1 and 2 are film laminates having two outer inelastic layers ofpolypropylene and a elastomeric core layer of astyrene-ethylene-butylenestyrene (SEBS) block copolymer. Two differentpolypropylenes were used. The inelastic skin layers delaminated from theelastomeric core layer in the elasticized regions of the film laminatehaving PP 3085 as the inelastic skin layers but delamination wasdifficult. No delamination was observed for the sample having PP 1024 asthe inelastic skin layers.

Examples 3-12 show that the addition of a stiffening aid, polystyrene,to the elastomeric core layer promotes delamination.

Examples 4-6 are examples of the effect of varying the amount ofpolystyrene added to the elastomeric core. No significant effects on thedelamination characteristics or elastic properties of the film laminateswere observed by varying the amount of polystyrene from 10-20 weightpercent. In Examples 8-10 the cast roll temperature was varied from80-180 deg F. (27-82 deg C.). Raising the cast roll temperature above120 deg F. (49 deg C.) did not influence delamination.

Examples 13-19 are film laminates having two outer inelastic layers ofPP 3085 polypropylene and an elastomeric core layer of astyrene-isoprene-styrene (SIS) block copolymer having 10 weight percentpolystyrene in the core. The skin layers easily delaminated from theelastomeric core layers for these samples. These examples alsodemonstrate that increasing the feedblock and die temperatures does notinfluence the delamination properties of the film laminates.

Examples 7, 8, 21 and 22 show that film laminates having a highercore-to-skin ratios (7:1) delaminate more readily than those with alower core-to-skin ratios (5:1).

Examples 23 and 24 show the effect of adding mineral oil to theelastomeric core. These samples delaminated more readily than sampleshaving elastomeric cores without any oil additive.

Examples 25 and 26 are film laminates having two outer inelastic layersof polyethylene and an elastomeric core layer of astyrene-isoprene-styrene (SIS) block copolymer having 10 weight percentpolystyrene in the core. The use of high density polyethylene and lowdensity polyethylene as the skin layers was investigated. The skinlayers easily delaminated from the elastomeric core layers for thesesamples.

Examples 27-32 show that the addition of 5 and 10 weight percent of anethylene vinyl-acetate copolymer to polypropylene skin layers promotesdelamination. A comparison of Examples 29 and 30 to Examples 31 and 32also shows that delamination occurs more readily when the elastomericcore is a styrene-isoprene-styrene block copolymer than it does when thecore is a styrene-ethylene-butylene-styrene block copolymer.

Examples 29 and 33 show that the addition of 10 weight percent ofpoly(alphamethylstyrene) to polypropylene skin layers promotesdelamination.

Example 34 is a film laminate having two outer inelastic layers ofpolypropylene and a polyurethane elastomeric core layer. This sampleshowed good delamination characteristics.

Example 35

An elastic film laminate sample having the following features wasprepared in a manner similar to Example 11:

    ______________________________________                                        Skin composition:  PP 1024                                                    Core composition:  K-1107                                                     Additives in core: 20% PS G-18.sup.1 and 0.5%                                                    Irganox ™ 1010.sup.2                                    C/S ratio:         7.25                                                       Film thickness:    2.5 mil (62.5 micron)                                      ______________________________________                                         .sup.1 Amoco polystyrene #1G18-C7 available from Amoco Oil Company            .sup.2 antioxidant available from CibaGeigy Corporation                  

The film laminate was stretched in the transverse direction at a ratioof about 6:1 and was then passed over a patterned heated roll (88° C.).This resulted in alternating parallel longitudinal bands of inelasticand elastic regions (approximately 1.5 mm in width) running in themachine direction of the film. A cyclical stretching and heating processas described above was used to affect delamination of the outerinelastic skin layers from the elastomeric core layer in the elasticizedregions of the film laminate.

The film laminate was then stretched 100% in the transverse directionand a nonwoven web typical of that used for disposable diaper coverstock(17 g/m² basis weight point-bonded spunbond polypropylene) was laminatedto one side of the film laminate through the use of an acrylate-basedadhesive transfer tape (#950 available from 3M Company).

Machine direction tensile strength data was obtained for the elasticfilm/nonwoven laminate using an Instron™ 1122 tensile tester. The testwas a modified version of ASTM D-882. A 1 in×3 in (2.54 cm ×7.62 cm)sample was placed at a 2.0 in (5.08 cm) gauge length and was stretchedat a rate of 20 in (50.8 cm) per minute. Six samples were tested. Thedata ranged from 5300-6000 gms/in(2.09-2.36 Kg/cm) width at 35-45%stretch. For comparison, tensile strength data was obtained for atypical diaper backsheet material, 1.5 mil (37.5 micron) thickpolyethylene film (available from Clopay). Values ranged from 1188gms/in (0.47 Kg/cm) width at 400% stretch to 1960 gms/in (0.77 Kg/cm)width at 730% stretch.

Example 36

An approximate 8 in² (20.3 cm²) piece of the elastic film laminateprepared above in Example 35 was stretched to 100% in the transversedirection and a center longitudinal zone measuring 4 in (10.2 cm) inwidth was subjected to a deactivating heat treatment (approximately 93°C. for one minute). This resulted in a film sample with an inelasticcenter region having adjacent elasticized regions on both sides of thecenter zone.

We claim:
 1. A disposable garment comprising an absorbent core structurehaving an absorbent core, a liquid-permeable inelastic inner layerhaving side edges and a liquid-impermeable outer layer having sideedges, and at least two elastic side panels at one end of the disposablegarment which side panels extend past at least the side edges of theliquid permeable inner layer or the liquid impermeable outer layer whichtwo side panels are formed by an elastic film laminate comprising acontinuous elastomeric core layer of at least a first thickness and atleast one continuous inelastic skin outer layer of oriented plastichaving a second thickness less than the first thickness, wherein thefilm laminate forming a side panel is divided into at least one elasticregion and at least one non-elastic region, the film laminate forming aside panel attached to the absorbent core structure in the at least onenon-elastic region.
 2. The disposable absorbent garment of claim 1wherein the elastic film laminate comprises a central inelastic portionand at least two elastic portions adjacent the central inelastic portionwherein the central inelastic portion is joined to the absorbent corestructure, and the at least two adjacent elastic portions form theelastic side panels.
 3. The disposable absorbent garment of claim 2wherein the central inelastic portion forms the liquid-impermeable outerlayer of the absorbent core structure.
 4. The disposable absorbentgarment of claim 3 wherein the elastic portions further comprisenon-elastic regions as a sealable strip at the outer side edges thereof.5. The disposable absorbent garment of claim 2 wherein the at least twoadjacent elastic portions provide for leg openings by cutout portions oneach adjacent elastic portion.
 6. The disposable absorbent garment ofclaim 2 wherein elastic side panels are provided at each of two opposingends of the disposable garment and opposing outer side edges of elasticportions, at opposing ends of the disposable garment, form a side seamattaching two opposing elastic side panels.
 7. The disposable absorbentgarment of claim 2 wherein the elastic film laminate is a strip attachedat the non-elastic portion to the absorbent core structure at a firstend and attached to a second opposing end of the core structure at theouter side edges of the elastic side panels.
 8. The disposable absorbentgarment of claim 7 wherein the non-elastic portion is permanentlyattached to the liquid-impermeable outer layer of the absorbent corestructure at the first end and releasably attached to the opposing endof the absorbent core structure at the outer side edges of the elasticside panels.
 9. The disposable absorbent garment of claim 8 wherein theouter side edges of the elastic side panels are provided withnon-elastic attachment regions, each provided with first attachmentmeans, which releasably attach to a second complementary attachmentmeans at the first end of the absorbent pad structure.
 10. Thedisposable absorbent garment of claim 9 wherein the first attachmentmeans comprises a pressure-sensitive adhesive attachment means.
 11. Thedisposable absorbent garment of claim 9 wherein the first attachmentmeans comprises a mechanical attachment means and the complementaryattachment means comprises a complementary mechanical attachment means.12. The disposable absorbent garment of claim 9 wherein the firstattachment means comprises a cohesive adhesive attachment means and thecomplementary attachment means comprises a complementary cohesiveadhesive.
 13. The disposable absorbent garment of claim 8 wherein anouter side edge of an elastic side panels is provided with an attachmentregion provided with a fastener tab which is permanently attached to theattachment region at a first end and provided with a releasableattachment means at a second distal end to releasably adhere to theopposing elastic portion.
 14. The disposable absorbent garment of claim13 wherein the releasable attachment means comprises male mechanicalfastener elements, and the elastic band is provided with a nonwovenmaterial adhered to the outer face engagable with the male mechanicalfastener elements.
 15. The disposable absorbent garment of claim 2wherein the elastic portions of the laminate are further characterizedin that the skin layer and core layer in the at least one elastic regionare detached.
 16. The disposable absorbent garment of claim 2 furthercharacterized in that the inelastic region is substantially flat and theskin layer is oriented in a first direction with the film laminate beingelastic, in said elastic regions, in said first direction.
 17. Thedisposable garment of claim 1 wherein the elastomeric core layer in thenon-elastic region having a thickness less than said first thicknesswhen the elastic film laminate is in the relaxed state and whichnon-elastic region elastomeric core layer is in substantially continuousplanar contact with the at least one outer skin layer, and when theelastic film laminate is in the relaxed state the elastomeric core layerin the at least one elastic region having said first thickness andhaving an overlying skin layer having an outer surface area greater thanthe planar surface area of the elastomeric core layer in the elasticregion in the relaxed state.
 18. A disposable absorbent garmentcomprising an absorbent core structure having an absorbent core, aliquid-permeable inelastic inner layer and a liquid-impermeable outerlayer and at least two elastic side panels which side panels extend pastat least the side edges of the liquid permeable inner layer or theliquid impermeable outer layer, said side panels being at least at oneend of the disposable absorbent garment, the side panels being formed byat least one elastic laminate having at least one elastic region and atleast two inelastic attachment regions at terminal ends of said elasticlaminate, on at least one of said inelastic attachment regions isprovided a first attachment element.
 19. The disposable absorbentgarment of claim 18 wherein the at least two inelastic attachmentregions are each provided with a pressure-sensitive adhesive region asan attachment element.
 20. The disposable absorbent garment of claim 19wherein the pressure-sensitive adhesive region is a patch of adhesive onthe inelastic attachment region.
 21. The disposable absorbent garment ofclaim 19 wherein the pressure-sensitive adhesive region are provided bypressure-sensitive adhesive fastening tabs attached to the inelasticattachment regions.
 22. The disposable absorbent garment of claim 18wherein at least one inelastic attachment region first attachmentelement is provided with at least one mechanical fastener region. 23.The disposable absorbent garment of claim 22 wherein the mechanicalfastener region is a mechanical fastener patch on the inelasticattachment region.
 24. The disposable absorbent garment of claim 22wherein the mechanical fastener region comprises male mechanicalfastener elements attached to two opposing inelastic attachment regionswhich male mechanical fastener elements are releasably attachable to acomplementary second mechanical attachment element at the opposing endof the disposable absorbent article.
 25. The disposable absorbentgarment of claim 22 wherein a mechanical fastener region is provided ontwo inelastic attachment regions by mechanical fastener tabs attached toeach of said two inelastic attachment regions.
 26. The disposableabsorbent garment of claim 25 wherein one end of each of said mechanicalfastening tabs is permanently attached to said inelastic attachmentregion at a proximal end with a distal end provided with male mechanicalfastening elements.
 27. The disposable absorbent garment of claim 26further comprising a complementary second mechanical attachment elementat the opposing end of the disposable article.
 28. The disposableabsorbent garment of claim 22 further comprising a complementary secondmechanical attachment element adjacent the opposing terminal end of saidelastic laminate.
 29. The disposable absorbent garment of claim 18wherein said at least one elastic laminate forms at least two elasticside panels adjacent two terminal inelastic attachment regions.
 30. Thedisposable absorbent garment of claim 29 wherein the elastic side panelsextend beyond the outer side edge of the absorbent core structure andthe inner and outer layers.
 31. The disposable absorbent garment ofclaim 22 wherein the elastic side panels extend beyond outer side edgesof the absorbent core structure and the inner and outer layers.
 32. Thedisposable absorbent garment of claim 22 wherein the elastic side panelextends over at least a portion of the absorbent core structure.
 33. Thedisposable absorbent garment of claim 18 wherein there is one elasticlaminate attached across at least one end of the absorbent corestructure forming two elastic side panels.
 34. The disposable absorbentgarment of claim 33 wherein a portion of the one elastic laminate isattached to an outer surface of the absorbent core structure.
 35. Thedisposable absorbent garment of claim 34 wherein the portion of the oneelastic laminate portion attached to the absorbent core structure is aninelastic attachment region.
 36. The disposable absorbent garment ofclaim 18 wherein the elastic laminate comprises a multilayer filmcomprising continuous elastomeric core layer of at least a firstthickness and at least one continuous inelastic skin outer layer oforiented plastic having a second thickness less than the firstthickness, wherein the film laminate is divided into at least oneelastic region and at least one non-elastic region, the film laminateattached to the absorbent core structure core layer in the at least onenon-elastic region, with elastomeric core layer in the non-elasticregion having a thickness less than said first thickness when theelastic film laminate is in the relaxed state and which non-elasticregion elastomeric core layer is in substantially continuous planarcontact with the at least one outer skin layer, and when the elasticfilm laminate is in the relaxed state the elastomeric core layer in theat least one elastic region having said first thickness and having anoverlying skin layer having an outer surface area greater than theplanar surface area of the elastomeric core layer in the elastic regionin the relaxed state.
 37. The disposable absorbent garment of claim 36wherein the elastic film laminate comprises a central inelasticattachment region and adjacent elastic portions wherein the centralinelastic attachment portion is joined to the absorbent core structure,and the adjacent elastic portions form the elastic side panels.
 38. Thedisposable absorbent garment of claim 37 wherein the central inelasticattachment region forms at least a portion of the liquid-impermeableouter layer of the absorbent core structure.
 39. The disposableabsorbent garment of claim 36 wherein the central inelastic attachmentregion is permanently attached to the liquid-impermeable outer layer ofthe absorbent core structure at the first end and the elastic laminateis releasably attached to the opposing end of the absorbent corestructure by the two terminal inelastic attachment regions firstattachment elements.
 40. The disposable absorbent garment of claim 36wherein the elastic portions of the laminate are further characterizedin that the skin layer and core layer in the at least one elastic regionare detached.
 41. The disposable absorbent garment of claim 36 whereinthe inelastic region is substantially flat and the skin layer isoriented in a first direction with the film laminate being elastic, insaid elastic regions, in said first direction.
 42. The disposableabsorbent garment of claim 18 wherein the at least one first attachmentelement releasably attaches to a complementary second attachmentelement.
 43. The disposable absorbent garment of claim 42 wherein thefirst attachment element comprises a cohesive adhesive attachmentelement and the complementary second attachment element comprises acomplementary cohesive adhesive.
 44. The disposable absorbent garment ofclaim 42 wherein the at least one inelastic attachment region firstattachment element is provided with a fastener tab which is permanentlyattached to the inelastic attachment region at a first end and providedwith a releasable attachment means at a second distal end to releasablyadhere to the opposing elastic side panel.